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S K Sengupta

Publications and source records attributed to S K Sengupta.

64 records · Page 4Linked to original sources
PubMed1975

7-substituted actinomycin D analogs. Chemical and growth-inhibitory studies.

The synthesis and biological activity of three 7-substituted actinomycin D derivatives are reported. Three such derivatives, 7-nitro-, 7-amino-, and 7-hydroxyactinomycin D, were synthesized via new methods which were first tested successfully with a chromophore model system. Of these, 7-nitro- and 7-aminoactinomycin D were assayed for growth inhibitory activity against mammalian cells (CCRF-CEM human lymphoblastic leukemia) in vitro and against the Ridgway osteogenic sarcoma and the L1210, P1534, and P388 murine leukemias in vivo. In these systems, the inhibitory activity of the 7-substituted analogs was comparable to actinomycin D. In two bacterial systems ( (L. casei and L. arabinosus) in vitro, on the other hand, these compounds showed inhibitory profiles which are distinctly different from actinomycin D. These studies demonstrate that substitution at the 7 position, which does not interfere with DNA binding, is capable of yielding experimental antitumor agents with significant activity against a variety of tumors.

Animals↗
PubMed1975

7-Amino-actinomycin D as a cytochemical probe. I. Spectral properties.

The optical absorption and fluorescence characteristics of 7-animo-actinomycin D were determined to evaluate its potential as a fluorescent cytochemical probe. At pH 7.0, the absorption maximum and fluorescence excitation maximum are both at 503 nm; the fluorescence emission is at 675 nm. When this compound forms complexes with DNA in solution, the absorption and fluorescence excitation maxima shift to 543 nm and the fluorescence emission shifts to 655 nm. The fluorescence quantum yield is 0.016 for 7-amino-actinomycin D free in solution and 0.01-0.02 for complexes with native DNA. The 7-amino-actinomycin D also exhibits fluorescence shifts characteristic of binding when put into solution with poly(dG-dC) poly(dG-dC), but not with poly(dI-dC) poly(dI-dC). The spectral characteristics are the same at pH 7.0 whether the solvent is 0.01 M PO4 with 0.0001 M EDTA or Earle's salts with 0.025 M N-2-hydroxyethylpiperazine-N1-2-ethanesulfonic acid.

Animals↗
PubMedDate not supplied

Integrating academic and community laboratory needs: developing a successful outreach program.

Remarkably few large regional laboratory programs involving academic health centers exist in Canada. We present a model of a successful laboratory outreach program established by the Queen's University Department of Pathology (Kingston, Ontario) and its affiliated hospital laboratories. Community hospitals in small urban and semi-rural areas benefit from a diffusion of specialty expertise in laboratory medicine and technology, which enables them to increase their local testing capabilities and improve turn-around time. Testing and services of a more complex nature are referred to the academic hospitals. The result has been a steady improvement in the quality of laboratory services in the region with increased cost-effectiveness through shared services and focused economies of scale.

Academic Medical Centers↗
PubMedDate not supplied

Promoting, building and sustaining a regional laboratory network in a changing environment.

The Queen's University Department of Pathology and its affiliated hospital laboratories (Kingston, Canada) have operated a successful laboratory outreach program for more than a decade in Southeastern Ontario. The outreach program provides high quality reference testing and technical and professional expertise in laboratory medicine to largely rural and small urban community hospitals. As a consequence of dramatic cuts to the publicly funded health-care system in the Province of Ontario, the environment in which laboratory medicine is practiced has altered irrevocably. This article discusses some of the difficult internal and external challenges faced by the outreach program within the region and how they were effectively managed, not only to maintain but to enhance the program's services. The result has been a continued improvement in the quality of laboratory services in the region with significantly increased cost-effectiveness, largely through reengineering and consolidation.

Budgets↗